Fuel compensating device for a supercharged type diesel engine

ABSTRACT

A fuel compensating device for a supercharged type diesel engine comprising large and small pressure receiving members in chambers, a connecting member connecting the pressure receiving members, a lever connected with the connecting member whereby a stopped position of the control rack is displaced at positions corresponding to smoke limit at non-supercharging and high supercharging of the control rack and increased quantity position at starting.

United States Patent [191 Okura Oct. 7, 1975 FUEL COMPENSATING DEVICEFOR A SUPERCHARGED TYPE DIESEL ENGINE [75] Inventor: Rikuo Okura,Kawagoe, Japan [73] Assignee: Diesel Kiki Kabushiki Kaisha,

Tokyo, Japan 22 Filed: Oct. 11, 1974 21 Appl. No.: 514,245

[30] Foreign Application Priority Data Oct. 17, 1973 Japan 48-115739[52] US. Cl. 123/140 MP,123/140 MC,

123/139 ST, 123/179 L [51] Int. C1. .....F02D 1/04; F02D 1/06; F02B H10[58] Field of Search 60/597, 601, 603; 123/139 ST, 179 L, 179 G, 140 J,140 MP [56] References Cited UNITED STATES PATENTS 3,577,969 5/1971Morton 123/140 MP 3,707,144 12/1972 Galis et a1. 123/179 L 3,795,2333/1974 Crews et al. 123/140 MP 3,814,072 6/1974 Gillespie 123/139 ST3,818,883 6/1974 Glassey 123/140 MP 3,820,519 6/1974 Suda et a1. 123/140MP Primary ExaminerWendell E. Burns Assistant Examiner-James W. Cranson,Jr. Attorney, Agent, or FirmHenry R. Lerner 57] ABSTRACT 3 Claims, 2Drawing Figures US. Patent Oct. 7,1975 3,910,245

FUEL COMPENSATING DEVICE FOR A SUPERCHARGED TYPE DIESEL ENGINE Thepresent invention relates to a fuel compensating device which isattached to a fuel injection pump and compensates, in response tosupercharging air pressure, fuel supplying to a supercharged type dieselengine.

In a supercharged type diesel engine various devices for compensatingfuel in response to variation of amount of supercharging air werealready proposed. As these devices are exclusively directed to thecompensating of heavy load and high speed, the compensating of low speedis not sufficient and particularly increase of fuel at starting is noteffected automatically.

An object of the present invention is to provide a fuel compensatingdevice which eliminates these defects and can effect supercharging inresponse to the requirements of an engine at low speed supercharging andengine starting.

Other objects of the present invention is to provide a fuel compensatingdevice which is simple in construction and may be constructed as a unitso that it can be used in combination with an injection pump and agovernor without disturbrance of shape of the injection pump and kindand shape of the governor.

In order that the present invention may be more readily understood,reference will now be made to the accompanying drawing in which:

FIG. 1 is a vertical sectional view of an embodiment of the presentinvention and FIG. 2 shows characteristic curves at idling of the engineand of the device shown in FIG. 1.

Referring now to FIG. 1, to a side surface of fuel injection pump 1 (tothe other side surface of which is normally fixed a governor) is fixed acase 2 by bolts 3. The case comprises three stepped chambers, a largediameter chamber 4, an intermediate diameter chamber 5 and a smalldiameter chamber 6. To the large diameter chamber 4 is fitted a highpressure receiving member or a piston 7 which is movable stroke S. Theouter portion of the small diameter chamber 6 and the inner portionintegral with the intermediate diameter chamber 5 are partitioned by alow pressure receiving member or a diaphragm 8. The piston 7 and thediaphragm 8 are connected by a connecting member or a bolt 9. To astepped portion at the intermediate portion of the bolt 9 is attachedspring receiving washers 10 which are movable distance L in thedirection of the piston 7 are engaged with the stepped portion by acompression spring 11. Between a stepped portion of the intermediatediameter chamber 5 and the piston 7 is mounted a compression spring 12which urges the piston 7 to the right in FIG. 1. A boss 13 of the piston7 abuts on the spring receiving washers 10 after the washers movedistance L, forming a stopper against the action of the bolts 9 and thusthe diaphragm 8. A lever 14 is swingably combinated at one end with thebolt 9 by a pin 15 and supported on a pin 16 provided on the case 2 as afulcrum and at the other end engages a fuel control rack 17 of aninjection pump, forming a stopper against movement of the control rack17 in the fuel increasing direction. Conducts l8 and 19 respectively areadapted to introduce engine supercharging pressure to the small diameterchamber 6 and the large diameter chamber 4.

The operation of this device is as follows:

The engine supercharging pressure is introduced through the conduits 18and 19 to the large diameter chamber 4 and the small diameter chamber 6and then the piston 7 compresses the spring 12 by the force responsiveto area difference between the piston 7 and the diaphragm 8, moves thediaphragm 8 and the bolt 9 together stroke S to the left in FIG. 1 andis stopped abutting on the stepped portion of the large diameter chamber4. In this time the spring 11 keeps distance L without compression dueto set load so that the stroke S of the piston 7 is transmitted throughthe bolt 9 to the lever 14 which is swung anticlockwise and thus a stopposition of the control rack 17 is determined accordingly. This isindicated on a line b in FIG. 2 in which abscissa is control rackposition R and ordinate is engine rotation speed N. As superchargingpressure is further increased, the pressure in the small diameterchamber 6 acting on the deaphragm 8 over comes a set force of the spring11 and moves the bolt 9 distance L to the right in FIG. 1, this beingindicated on a line C in FIG. 2, so as to swing the lever 14 clockwise.Therefore the stop position of the control rack 17 is moved in the arrowdirection (fuel increasing direction) in FIG. 1, this being indicated bya line (1 in FIG. 2. If supercharging pressure lowers from a state ofthe line b, the piston 7 acts stroke S to the right by the force of thespring 12 so that the stop position of the rack 17 moves in the arrowdirection by the clockwise rotation of the lever 14. This is indicatedby a line a or a in FIG. 2. The spring 12 and a governor idling springare adapted to have characteristic comfirming to the requirement of theengine. For example a heavy set load of the spring 12 makes acharacteristic the line a. The line a shows fuel increase at the lowspeed and starting, the line b shows smoke limit at nonsupercharging,the line c shows fuel supercharge at high speed, line d shows smokelimits and line e shows upper limits of rotation in the controlcharacteristic curve.

I claim:

1. A fuel compensating device for a supercharged type diesel engine,comprising three stepped chambers forming a case, a large pressurereceiving member and a small pressure receiving member reciprocable inthe chambers by supercharging air pressure of the engine and springforces, a connecting member connecting the pressure receiving memberscoaxially and provided with springs therebetween and a lever serving asa stopper in the fuel increasing direction for a fuel control rack in afuel injection pump and being connected with the connecting member sothat in low supercharging pressure the small pressure receiving memberand the connecting member are movable by movement of the large pressurereceiving member and in high supercharging pressure the connectingmember alone is movable by the small pressure receiving member.

2. A fuel compensating device according to claim 1 wherein a spring isprovided between the large pressure receiving member and a steppedportion of the intermediate chamber.

3. A fuel compensating device according to claim 1 wherein an anotherspring is provided between the large pressure receiving member and astpped portion of the connecting member.

1. A fuel compensating device for a supercharged type diesel engine,comprising three stepped chambers forming a case, a large pressurereceiving member and a small pressure receiving member reciprocable inthe chambers by supercharging air pressure of the engine and springforces, a connecting member connecting the pressure receiving memberscoaxially and provided with springs therebetween and a lever serving asa stopper in the fuel increasing direction for a fuel control rack in afuel injection pump and being connected with the connecting member sothat in low supercharging pressure the small pressure receiving memberand the connecting member are movable by movement of the large pressurereceiving member and in high supercharging pressure the connectingmember alone is movable by the small pressure receiving member.
 2. Afuel compensating device according to claim 1 wherein a spring isprovided between the large pressure receiving member and a steppedportion of the intermediate chamber.
 3. A fuel compensating deviceaccording to claim 1 wherein an another spring is provided between thelarge pressure receiving member and a stpped portion of the connectingmember.